The present invention relates to the field of imaging in general, and more particularly, to ultrasound imaging.
One common method of assessing the efficacy of a given treatment for a disease is to compare ultrasound images of an affected tissue both before and after the treatment. Unfortunately, it may be difficult to compare the xe2x80x98beforexe2x80x99 and xe2x80x98afterxe2x80x99 images if some of the affected tissue is not present in both images or if the images are not aligned with respect to each other.
In stress-echo type heart studies, portions of the heart can be scanned before and after a stress test to provide corresponding before and after images of selected portions of the heart. Unfortunately, it can be difficult to scan the same portions of heart in the before and after tests using current technology. In particular, it can be difficult to reliably scan the same portion of the heart using a two-dimensional (2D) ultrasound system (or scanner). For example, during the before scan, the 2D scanner may capture a single xe2x80x9cslicexe2x80x9d of a portion of the heart under investigation. It may be difficult for the operator to capture the same portion of the heart after the stress test because, for example, the patient is breathing harder or because the heart is beating faster and moving to a greater extent within the patient""s body than before the stress test. This can mean that the before and after slices may not show the same portions of the heart and that a physician may have to mentally visualize the anatomy based on the differing 2D scans and correct for the differences between the before and after slices, which can be difficult.
Embodiments according to the present invention can provide methods and systems for aligning views of ultrasound data using transforms. Pursuant to these embodiments, a first ultrasound dataset that represents an object in a first coordinate system can be acquired at a first time. A plurality of landmarks of the object can be located in the first ultrasound dataset to define a second coordinate system. A first transform from the first to the second coordinate system can be determined for the first ultrasound dataset. A second ultrasound dataset that represents the object in the first coordinate system can be acquired at a second time. The same landmarks in the second ultrasound dataset can be located to define a third coordinate system. A second transform from the first to the third coordinate systems can be determined for the second ultrasound dataset.
By aligning the views, differences and similarities between the views may be readily observed, thereby possibly reducing the need to mentally visualize the anatomy, which can reduce the variability in diagnoses and lead to better treatment.
The present invention may allow two or more views of ultrasound image data to be aligned with respect to common anatomical features and display views of these features side by side while the stored data set is being recorded, is playing, or is paused, such as in a stress echo test. This may allow the user to directly compare ultrasound data acquired at different times, possibly from different locations and/or orientations. This may allow the data to be collected more quickly since the user may not have to examine as many views of the heart. Reducing the exam time may allow more patients to be seen in a day and help ensure that a stress echo test, taken after the patient""s heart rate has been increased through exercise or drugs, can occur during peak heart rate.
In some embodiments according to the present invention, a first view of image data in the first ultrasound dataset is displayed in the second coordinate system using the first transform and a second view of image data in the second ultrasound dataset is displayed in the third coordinate system aligned with the first view using the second transform. In some embodiments according to the present invention, the first and second views are displayed on a single display. In still other embodiments, the first and second views do not include any of the landmarks.
The act of locating a plurality of landmarks of the object in the first ultrasound dataset can be performed by locating a first one of the landmarks in a first view of image data in the first ultrasound dataset and a second one of the landmarks in a second view of image data in the first ultrasound dataset that is different from the first view.
In other embodiments according to the present invention, a series of first views of image data in the first ultrasound dataset are displayed and a series of second views of image data in the second ultrasound dataset are displayed, wherein respective ones of the first views are aligned with respective ones of the second views.
In still other embodiments according to the present invention, the first view of image data has an associated first time within a cycle associated with the object and the second view of image data has an associated second time within the cycle that is different than the first time.
In still other embodiments according to the present invention, views of ultrasound data can be provided so that the views appear to have been acquired from a different location and/or orientation. Pursuant to these embodiments, an object can be scanned to provide an ultrasound dataset that represents the object in a first coordinate system. A second coordinate system can be determined that is different than the first coordinate system. A transform can be determined for image data in the ultrasound dataset from the first coordinate system to the second coordinate system. A view of image data in the ultrasound dataset in the second coordinate system can be displayed using the transform. In some embodiments according to the present invention, the transform can be determined by locating at least three landmarks of the object in the ultrasound dataset.
In further embodiments according to the present invention, the transform can be changed based on user input to provide a second transform and a second view of image data in the ultrasound dataset which can be displayed using the second transform. In some embodiments, the user input can be provided via a trackball or other type of input device. In still other embodiments, an instrument can be guided in a body that contains the object based on the view while scanning is performed.